1. Field of the Invention
The present invention relates in general to network communications and, more specifically, to a system having fixed and mobile wireless transceivers with dynamic routing based on quality-of-service criteria in order to optimize data transfers in a network with dynamically changing topology.
2. Background of the Invention
Wireless networks are gaining in popularity. Standards such as 802.11a, 802.11b, 802.11g, Bluetooth, Ultra Wideband (UWB), etc., allow users to connect wirelessly via portions of the radio-frequency spectrum. As the cost of wireless network systems decreases and their popularity increases, these systems are becoming more prevalent. Some provide channels for relatively unrestricted transfer of information among various devices. The devices can be owned or operated by different users without formal registration, certification, administrator approval or other access restrictions. In cases where mobile wireless transceivers are used, there can be a constant change in the number and type of devices accessing a wireless network.
The types of wireless systems available today have shortcomings for some applications. The 802.11a, 802.11b and 802.11g standard systems have two modes of operation: infrastructure and Ad-Hoc. The infrastructure mode uses a dedicated radio controller and is primarily designed to provide a direct wireless link to a standard Ethernet network connection. The “Ad Hoc” approach allows for peer- to-peer networking, so that a very small network of several PCs on the same wireless channel can share files. The nodes in this network control their own access to the wireless media. The Ad Hoc mode is primarily used to temporarily interconnect a few computers together where an Ethernet backbone may not be available or an emergency network is required. There is no means of gaining access to the corporate Ethernet network or an Internet connection. As such, neither scheme is designed for “multi-hop” transmission. In a “multi-hop” scheme, data is transferred through intermediary wireless transceivers before arriving at the destination receiving device.
Generally, the quality of a communications channel in a wireless network is not guaranteed so that, for example, a software process executing on a device is not guaranteed a specific transfer rate over any given interval of time. This makes it very difficult to provide services that require a consistent bit or packet error rate (BER or PER); services such as streaming media, video and audio fall into this category.
Other approaches to wireless communications do not provide a comprehensive system design approach. For example, UWB only defines a radio physical layer. This merely defines how bits will be transmitted on the radio interface physical connection. There is no definition for a flexible protocol to allow coordination of devices, channels, links, etc., within a UWB wireless network. Bluetooth does include several features for point-to-point communications between devices, but does this based on a master-slave relationship that is difficult to use in a network with changing topology, such as one made up of mobile wireless transceivers. In addition, all the nodes within the Bluetooth network must be able to see at least the master for coordination purposes. This clearly limits the operational range of the network.
Other considerations for a flexible wireless communication system include scalability, range, user interface presentation, network management, minimization of radio interference, creation of user features to generate market desirability, security and access controls, physical design, features and operation of the devices, etc.
Hence, it would be desirable to provide a wireless network that employs a dynamically changing topology to accommodate user mobility and that is also capable of accepting and handling heterogeneous user traffic from multiple devices in a more efficient manner.